In this opening commentary, we highlight the development of the teaching and learning of Chinese as a second or foreign language (CSL/CFL), which has attracted much attention from researchers, language educators, and other stakeholders worldwide. To contribute to this ongoing examination and discussion, this special issue documents the collective efforts of scholars in different educational contexts to review six critical issues in teaching and learning CSL/CFL: learning and instruction of reading Chinese as an additional language, Chinese character teaching and learning, learner identity in CSL/CFL education, teaching and learning Chinese through immersion, technology assisted CSL/CFL teaching and learning, and mobile assisted learning CFL. We contend that all efforts to address these critical issues require constant examination to facilitate further development in CSL/CFL education around the world.